Steam-generator



(N0 M0del.)

J. H. KENDALL. STEAM GENERATOR.

N0. 529,391. Patented Nov. 20, 1894.

waay JAMES H. KENDALL, OF CAMBRIDGE, MASSAOI-IUSE'ITS.

STEAM=GENERATOR.

SPEGIFIGATION forming paart of Letters Patent N0. 529,391, dated November 20, 1894.

' Application fi1ed Rbruary 19. 18941 Seri.l N0. 500,690. (N mode1.)

T0 all wh0m zit may concern:

Be it known tha1; I, JAMES H. KENDALL, of Cambridge, county of Middlesex, and State 0f Massachusetts, have invented an Improvement in Steam-Generat-ors, of whieh the following deseription, in conneetion With the acconnpanying drawings, is a specifieation, like leuters 0n the drawings 'representing 1ike parts.

My invention relating to steam generators is shown embodied in an apparatus comprising a furnace and horizontal retnrn flue boiler, the object of the invention being to prodnee a steam generator eapable of carrying high pressures wiLh efficieney and safety. With steam generators 0f this dass and others where the boiler she1l constitutes the top of the fire box or furnace proper er where there is a erown sheeb in such relation to the fire box, it is unsafe t0 use p1ates 0f very greai: thickness thns exposed to the direet radiant heat of the fire as the plate 0r a portion thereof is likely t0 become heated much in excess of the temperature of the water in the boiler, espeeially if any Sediment aeeurnulates over the plante, and under such conditions the p1ate may softem so as to yie1d under the high pressure carried in the boiler.

In the steam generator forming the subjeet of this invention a nun1ber of eircula'ning tnbes are interposed between the fire and the portion of the boiler directly over the fire box, said tnbes thus constibuting a.- screen 0r parbition, either alone or preferably in eonjunction with refractory material supported over them, between the fire and heiler shell, and thus themselves receive the direet heab radiated frorn the fire and protect the boiler shell fronn the direct radiant heat so that the heiler shell cannot be heated snbstantially above the temperature of the water contained in it and n1ay thus be 1nade 0f any desired thiekness necessary for the pressure t0 be carried by the boiler, withont danger of being softened or weakened by the aetion of the fire. Vhen the invention is embodied in a horizontal return fiue heiler the said sereen is preferably extended snbstantially the en= tire length of the boiler over the furnace proper, bridge Wall, and combustion ehamber at the rear thereof.

The invention is capable of eonsiderable veriation as to details of construction and arrangernent and it is not 1ixnited to the specific consruction herein shown.

Figure 1 is a longitudinal vertical section of the steam generator embodying this invention; Fig. 2, a transverse vertical seetion 0n the plane indicated by the broken 1ine m Fig. 1, and Fig. 3 a diagram view illustrating in transverse vertical section a modifioation t0 be referred to.

The boiler a may be 01": any suitable or nsna1 construetion being herein shown as of the retnrn flne type, and the heiler setting b is herein shown as of masonry 0f the usuai construotion exeept that the heiler may be somewhat higher in the setting than in the usua1 eonstrnction of stearn generators of this clasS. In the freut portion 0E the setting is the usna1 fire bbx containing the grate bars c separating the fire chamber above from the ash pit below anti the bridge weil d at the rear of the fire ehan1ber over which the prodncts 0f combustion pass into the combustion channber e, thenee under the areh f and through the vertical flue g, into the rear end 0f the flues of the heiler through which they pass, to the uptake (not shown) located over the opening h a1: the front of the flue sheet the position of whieh is indieated by the 1ine 0f rivets at i, Fig. l.

Instead of having the she1l of the heiler a itse1f constitnte the top of the fire and combustzion chambers as has been usually practieed With steam generators of this kind, there is in accordanee With this invention a series of eirculating tubes k interposed between the top of the fire chamber and preferably of the combustion channber, and the bo1atonn of the heiler, said tubes being shown as extending transversely from side to side 0f the heiler senting ELI1C1 eonnecting at one end With a longitudinal drum m communieating by pipes n with the 10wer part of the interior of the boiler while the other ends of the eirculating pipes connect with another longitudinal pipe or manifold 0 that eommunicates with the boi1er throngh pipes p, entering the interior 0f the heiler ab sonne distance above the point of connection of the pipes n es shown. As

shown in this instance, the cireulating pipes 10 are sei; in inclined position, their lower ende being conneeted With the drurn m and higher IOO ends with the manifold in order to enhance the circulation from m to o. Tho said cirou- 1ating pipes 7c thns receive the heat direotly radiated from the firo and from the combustion in the cornbustion chamber a1: the rear 0f the bridge Wall ancl servo to protect the shell of the boiler from such heat, am]. in order to afford a more effioient screen for the bottom of the boiler and. t0 more efficiently direet the prouots of combustion 130 pass underthe areh f int0 the rear vertical flue g the said eirculating pipes k are shown as support in g upon them a layerr of refraotory material, thus affording therewith a oomplete soreen or partition bot ween oho fire and. the boilor Shell.

'1he Clrun1 m am]. manifold 0 are provided with suitalole hand-holes for acoess 130 their interior and said manifold 0 also has band holes opposite the eixeulating pipes to faoilitate the Substitution ancl removal 0f the pipes when reqnired.

By the arrangernent shown, there Will be a. natural cireulation of water from the bottom of the boiler thr0ugh the pipes n into t;he drn1n m, thenoe through the ciroulating pipes t0 'he manifold 0 and pipes p to a higher point in ehe boiler, and the sedimen will naturally acoumulate mainlyin Lhe drurn m from whioh i'm may be reaclily removed, the blowoff pipe t for the boiler being shown as counecting with the bottoxn of said drum m as shown in Fig. l, and the feecl water may be introduced into the drum m through thls or another snitable pipe.

The boiler is shown as having its rear end supported upon the arch fof the masonry ancl also by hangers u while tho front end of the boiler is snpported mainly from the hangers 10 depending from cross bars w supported on suitable piers at the side 0f the boiler setting.

It is not necessary that the arrangement should be as shown in all particulars. In

some cases, it may be desirable to use a donble fire box, as shown for oxample in Fig. 3,

in which caso there may be a Single drurn m over the rniddle of theboiler setting oonnected by circulating pipes with manifolds 0 one at ea,ch side of the setting, the arrangennent being otherwise substantially the same as shown in tho other figures.

By the herein deseribed construelzion, the entire boiler Shell is protected from the heat radiated from the fire and largely from any direcb eontact with the products of cornbustion which mainly affeet the water in the cironlating tubes and around. the fiues of the boiler, and thus while effioient heating surface is afforded for the generation of steam there is no danger of over-heating the shell of tl1e heiler itself, whieh may be of such thiekness aus may be requiredto withstand oho internal pressure, the thiokness not being limited by the requirernents of the conduction of heat throngh the metal ot the shell itself, as is the ease when the boiler Shell is exposed d'ireotly to the fire.

I claim The connbination of a horizontal xetnrn flue boiler With a drum at one side ot' the fire box OI' ofn portion thereof oonneotecl with the lower part ot Ehe boiler; a manifold at the other side of the fire box, conneoted Wlth the boiler at a higher point than the drum, and a series of eiroulating pipes extending fron1 said rlrnm to said manifold aeross the top of the fire box, between the sa1ne and the boiler shell, and a oovering supported. thereon and constituting therewith a. soreen whieh prevents the heated produuts from co1ning in contact with the boiler shell, substantially as and for Ehe pnrpose desorlbed.

In testimony whereof I have signed my nan1e t0 this speoifioation in tho presence of two subscribing wltnessos.

JAMES H. KENDALL.

W'itnesses:

J os. P. LIVERMORE, M. E. HILL. 

